VA Surgeons Use Less Off-Pump CABG

Action Points

Surgeons within the VA health system have become less likely to perform CABG without the support of cardiopulmonary bypass (off-pump) in recent years.

Point out that mortality was consistently high for cases that involved a conversion from an off-pump to on-pump procedure.

Surgeons within the Veterans Affairs health system have become less likely to perform coronary artery bypass grafting (CABG) without the support of cardiopulmonary bypass in recent years, researchers found.

The use of off-pump CABG peaked in 2003 -- when it accounted for 24% of such operations -- and fell to about 19% by 2011, according to Faisal Bakaeen, MD, of the Michael E. DeBakey VA Medical Center in Houston, and colleagues.

From 1997 to 2011, perioperative mortality dropped for both off-pump and on-pump CABG, remaining below 2% since 2006, the researchers reported online in JAMA Surgery.

Mortality was consistently high, however, for cases that involved a conversion from an off-pump to on-pump procedure.

"The clinical implication of this study is that for the average VA surgical practice, there should be no pressure to either perform or avoid [on-pump] CABG," Bakaeen and colleagues wrote. "Rather, the focus should be on which is the best approach for the patient. Converted cases have higher mortality, and this should be considered when planning an operation and in the formulation of the perioperative care."

To avoid potential complications associated with cardiopulmonary bypass, some surgeons started using off-pump CABG.

Recent trials comparing on-pump versus off-pump CABG -- including the ROOBY trial and the CORONARY trial -- have failed to show a significant difference in hard clinical endpoints, although there have been some differences in secondary endpoints.

In the ROOBY trial, off-pump CABG was associated with reduced patency of bypass grafts and less effective revascularization. In the CORONARY trial, off-pump CABG was associated with less need for reoperation for perioperative bleeding and fewer cases of acute kidney injury and respiratory complications, but an increased need for early repeated revascularization.

To see how the use of off-pump CABG changed over time, Bakaeen and colleagues analyzed data from the VA Surgical Quality Improvement Program (VASQIP). The study included 65,097 patients who underwent CABG at one of the 42 cardiac surgery centers in the VA system from October 1997 to April 2011.

During the entire study period, 17.9% of the operations were performed without cardiopulmonary bypass.

The decline in use following the 2003 peak "reflects the reality that although [off-pump] CABG offers the advantage of avoiding cardiopulmonary bypass and aortic manipulation, it is an inherently more technically difficult operation to perform," according to the researchers.

The rate of conversions from off-pump to on-pump operations (associated with elevated mortality rates) fell over time (P<0.001 for trend), staying below 3.5% from 2007 to the end of the study period.

The conversion rate was lower, however, among the seven centers that performed high volumes of off-pump CABG (1.8% versus 3.6%, P<0.001). These centers did not experience a decline in the rate of off-pump operations, which remained above 50%.

"High-volume [off-pump] centers are best suited to taking on the challenge of training future surgeons in valuable [off-pump] skills, and the routine use of [off-pump] CABG might some day be confined to these high-volume centers," Bakaeen and colleagues wrote.

"It is clear that [off-pump] CABG will continue to have a role in the foreseeable future," Edward Sako, MD, PhD, of the University of Texas Health Science Center at San Antonio, wrote in an invited commentary. "Its use will continue to be driven by those who feel comfortable with the technique and this will not necessarily be a result of formal training."

The study authors noted that the study was limited by the lack of center- and surgeon-level data, the possibility of missing some conversions, the uncertain accuracy of categorizing conversions as planned or unplanned, and the uncertain generalizability of the findings to populations outside of the VA system.

Sako, however, said that the findings could have relevance beyond the veterans included in the study.

"Studies of the treatment of coronary artery disease in this population also are widely applicable to the male population of the U.S. at risk because the risk factors are mirrored in the two groups," he wrote.

The Michael E. DeBakey VA Medical Cardiovascular Center of Excellence funded the study. The CICSP-X study (the cardiac portion of VASQIP) was initially funded by a VA Health Services Research and Development grant, with ongoing support from the Office of Patient Care Services, VA Central Office, Washington, D.C. This project was supported in part by the Offices of Research and Development at the Northport and Eastern Colorado Health Care System Denver Veterans Affairs Medical Centers.

The study authors reported that they had no conflicts of interest.

Sako reported that he had no conflicts of interest.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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